Kellahan is an internationally exhibited artist with 18 years painting and curating experience. In 2011 she was selected to represent New Zealand at the Biennale of Chianciano in Italy. 160 artists worldwide participated, Kellahan won third place in the Leonardo Prize, Works on Paper category.

In 2011 she was a finalist and in 2009 Kellahan won the prestigious trans-Tasman Cricket Art Prize in Australia. Her work was exhibited around Australia. Kellahan has exhibited at the 2006 Florence Biennale in Italy, and her work featured in Denis Robinson's book, 'New Zealand's Favourite Artists'.

Predominantly self-taught, she attended courses at Central St Martins and Camberwell College of Arts in London. Her work was selected by the Royal Academy of Arts, London in 2000.

Born of a mind fascinated by tension and abstraction, Kellahan's paintings draw on atmospheric ambiguity and intuition. She manipulates scale, organic textures and constrained tonal variety to achieve strong works imbued with light and potency.